Basal cell carcinoma invasion depth determined with 30 and 75 MHz high-frequency ultrasound and histopathology – A comparative study

Abstract

Aim: To compare the depth spread of basal cell carcinoma (BCC) measured by histological examination and high-frequency ultrasound (HFUS) imaging with 30-MHz and 75-MHz probes. Materials and methods: HFUS skin imaging was used to examine 27 BCCs. A specialized high-resolution digital ultrasound imaging system DUB (TPM GmbH, Germany) with 75-MHz and 30-MHz probes was used. After HFUS scanning, the BCCs biopsy samples were collected by punch biopsy or surgical excision for the morphological examination. Based on the histomorphology results obtained, the tumors were divided into thin (≤1 mm invasion depth) and thick (>1 mm invasion depth). Each BCC spread depth was measured during the HFUS examination with 75-MHz and 30-MHz ultrasound probes and morphological examination. Results: Thin BCCs average invasion depth measured histologically was 0.494±0.212 mm. Its average depth obtained with HFU examination with 75-MHz and 30-MHz probes was 0.591±0.265 and 0.734±0.123 mm, respectively. High, statistically significant correlation between the histological and 75 MHz HFU measurements was obtained (r=0.870). The correlation was weak (r=0.290) when using a 30 MHz transducer. The average thick BCC invasion depth values obtained with the histological examination and 30 MHz HFUS scanning was 1.845±0.718 mm and 1.995±0.699 mm, respectively. High, statistically significant (r=0.951) correlation between the thick BCC spread depth measured with 30 MHz transducer and histomorphological examination was obtained. Conclusions: In cases of BCCs with thickness of ≤1 mm, there was a high correlation (r=0.870) of the tumor spread depth between micromorphological measurements and the results obtained using a 75 MHz transducer and in cases of BCCs with thickness of >1 mm, a very high correlation (r=0.951) of the tumor spread depth was observed between histomorphometry and 30 MHz transducer measurements.